Field of the Invention
The present invention relates to a gripper, and more particularly to a gripper capable of lifting a work piece.
Related Prior Art
FIG. 1A shows a gripper of a manipulator disclosed in Japan Patent (JP 2007118148A), wherein springs 101 cooperate with a pair of wedge mechanisms each of which consists of a clamping jaw 102 and a gripping member 103 to improve gripping stability. When a work piece 104 gripped by the gripper slides downward, the gripping members 103 will move along with the work piece 104 to produce an inward clamping force to prevent dropping of the work piece 104. However, after the gripper grips the work piece 104 but prior to moving it to the destination, an extra power source is required to lift the work piece 104, which highlights the disadvantage of low efficiency. Besides, this gripper further has the following disadvantages: the gripper can not be inverted, otherwise it is unable to maintain clamping force; the position of the work piece 104 is likely to change during the clamping process, which makes the locating operation difficult when releasing the work piece.
FIG. 1B shows another gripper of a manipulator disclosed a Chinese Patent (CN 103358314B), wherein a spring 113 is connected between a chuck 112 and a body 115, before gripping, the unopened gripper 111 moves downward along with the chuck 112 to make the spring 113 produce a prestress. When the chuck 112 opens, the prestress of the spring 113 is released to push down the gripper 111, as a result, the clamping jaws 111A move along the lateral edge of the work piece 114 while pushing away neighboring work pieces 116, so that the gripper 111 is able to pick up one of the work pieces 114 even when there are many work pieces 114 closely arranged in parallel. However, after the gripper 111 grips the work piece 114 but prior to moving it to the destination, an extra power source is required to lift the work piece 114, which highlights the disadvantage of low efficiency. Besides, this gripper further has the disadvantage that the gripper 111 is structurally complicated and inconvenient to operate.
FIG. 1C shows a gripping device as disclosed in US Patent (U.S. Pat. No. 9,335,337B2), wherein gears 121, a lead screw 122 and a linkage mechanism 123 cooperate with one anther to enable the clamping jaws 124 to grip and lift the work piece 125 simultaneously. Although the work piece 125 can be lifted while being gripped, the gripping operation requires the use of the gears 121, the lead screw 122 and the linkage mechanism 123, especially the use of the linkage mechanism 123 to grip the work piece 125, which highlights the disadvantages of complicated structure and insufficient structural strength. In addition, once the size of the finger portions 124A of the clamping jaws 124 is fixed, the linkage mechanism 123 restricts the movement of the clamping jaws 124, consequently restricting the capability of gripping other sized work pieces 125.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.